kane county stormwater technical guidance manual - Kane County, IL

Nonresidential Buildings
The lowest floor, including basement of all new construction or substantial
improvements for nonresidential buildings must either be elevated above the
FPE or be structurally dry floodproofed. The dry floodproofing must be
effective below the FPE and certified by an Illinois Professional Engineer or
Registered Structural Engineer. The certification of the dry floodproofing
performance should be stamped on the site plan and the overall building and
site plans must be approved by the Administrator. Additionally, the attendant
utilities must be watertight and capable of withstanding the base flood. The
dry floodproofing must either make the building watertight or be automated
with a backup power source requiring no human intervention. The NFIP
regulations (§ 60.3(c)(4)) require the community NFIP official to maintain a
record of approved buildings and the elevations to which they are
floodproofed.
Manufactured Homes and Recreational Vehicles
The Ordinance contains additional criteria, mandated by NFIP regulations,
related to placing manufactured homes or recreational vehicles in the
floodplain. Under the Ordinance, this includes existing manufactured homes
moved to a new site and new manufactured homes at a new or existing site.
Protection from flood damage below the FPE is required if the manufactured
home or recreational vehicle will be installed on a site for more than 180 days.
The applicant should refer to the Illinois Manufactured Home Tie-Down code.
Auxiliary Structures
Auxiliary structures such as tool sheds and detached garages on an existing,
single-family platted lot, may be constructed with the lowest floor below the
FPE provided that requirements of Article 4, § 407(d) are met for restrictions
on construction, use, structure size and value. Applicants should indicate on
the site plan the number and location of buildings which are in this category.
More than one such structure on a single-family lot may require a hydraulic
analysis to properly assess the impact on the existing or proposed floodplain.
§ T408 Non-Conforming Structures
A structure that is non-conforming to the Ordinance contains a lowest floor,
including basement, which is below the FPE. A non-conforming structure that
is damaged by flood, fire, wind or other natural or man-made disaster may be
restored on-site as long as the damage does not exceed 50% of its market
value prior to being damaged. Damage in excess of 50% of the structure’s
market value places the restoration into the substantial improvement category
and therefore, the building must conform to the requirements of Article 4, §
407.
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